TIM GANNON FILE PHOTO | Bridget Fleming (right) will oppose Senator Ken LaValle in a November election.

Southamptown Town Councilwoman Bridget Fleming won in a landslide over Jennifer Maertz of Rocky Point in a Democratic primary to face Senator Ken LaValle in November, unofficial results from the Suffolk County Board of Elections indicate.

Ms. Fleming, 52, of Sag Harbor received 79 percent of the votes Thursday with 2,031 cast in her favor to Ms. Maertz’s 531.

Ms. Fleming was an assistant district attorney in New York City, where she prosecuted sex crimes and headed a unit that prosecuted fraud in public programs. She was elected to fill a vacant seat on the Southampton Town Council in 2010, and won a full four-year term last year.

Ms. Maertz, 36, is an attorney from Rocky Point, and lost to 36-year incumbent Mr. LaValle two years ago when she stepped in after candidate Regina Calcaterra was taken off the ballot due to a residency issue.

During a debate last month, both Ms. Maertz and Ms. Fleming criticized Mr. LaValle (R-Port Jefferson) as a “part of the culture in Albany” that has not sought more tax allocations for the East End from around the state.

Both candidates said they support same-sex marriage and argued that changes needed to be made to the 2 percent tax levy cap passed by the state last year.

They differed on the important of campaign financing, with Ms. Fleming saying she stood the best shot of beating Mr. LaValle due to her leftover campaign funds, while Ms. Maertz said voters should choose based on a candidate’s positions, not the size of their warchest.