DEMOCRATS, who already dominate the state Legislature, have a good chance of picking up more seats on Tuesday.

The numbers are in their favor. Of the 200 seats in the Legislature, only 72, or 36 percent, are being contested. That means 115 Democrats and 13 Republicans are already assured of victory on Tuesday. In the contested races, Democrats have a big financial advantage, outspending their Republican rivals by an overall 2-1 margin, according to campaign finance reports through October 19.

Even in many of the races where a Republican incumbent is standing for reelection, Democrats have a fundraising advantage. There are some exceptions, races where Republican challengers are outspending Democratic incumbents, but overall the odds favor the Democrats to pick up some seats.

Here is the breakdown by branch:

In the Senate, 23 Democrats and two Republicans are facing no opponents and are assured of victory. That leaves 15 contested seats. Democrats have a fundraising advantage in 11 of the races, while
Republicans hold the fundraising edge in four.

Democrat Rebecca Rausch of Needham has spent $108,856 so far this year trying to unseat the Republican incumbent, Sen. Richard Ross of Wrentham. Ross, who has kept a low profile in the race and refused to debate Rausch, has spent just $12,733.

Two Republican incumbents – Sens. Vinny deMacedo of Plymouth and Dean Tran of Fitchburg – have outspent their Democratic rivals. But two other incumbents, Sens. Ryan Fattman of Sutton and Patrick O’Connor of Weymouth, are being outspent by their opponents. Katie McBrine of Hingham has spent $56,304 challenging O’Connor, who has spent $48,138. Thomas Merolli of Mendon has spent $43,605, more than twice as much as Fattman.

Two Democratic incumbents are being outspent by their challengers. Republican Margaret Busse of Acton has spent $147,226 taking on Sen. Jamie Eldridge of Acton, who reported spending $90,374. And Republican Steven Hall of Sturbridge has spent $20,520 taking on Sen. Anne Gobi of Spencer, who wasn’t far behind at $18,200.

In the House, 92 Democrats and 11 Republicans are facing no opponents and are assured of victory. That leaves 53 contested seats. Democrats have a fundraising advantage in 35 of the races, while
Republicans hold the fundraising edge in 21. In one race, Rep. Susannah Whipps, an independent, has the fundraising edge over her Democratic challenger.

Democratic challengers have outspent seven Republican incumbents, including Reps. Leonard Mirra of West Newbury, Bradford Hill of Ipswich, James Lyons of Andover, Todd Smola of Warren, Susan Gifford of Wareham, David DeCoste of Norwell, and Donald Berthiaume of Spencer.

Republican challengers, meanwhile, have outspent four Democratic incumbents – Reps. Brian Ashe of Longmeadow, Colleen Garry of Dracut, Joan Meschino of Hull, and Brian Murray of Milford.

How the races featuring incumbents in the Senate and House turn out will probably determine whether the Legislature becomes even more a fiefdom of Democrats than it currently is.