Democratic Assemblyman Bob Andrzejczak and running mate Bruce Land beat the Republican ticket in southern New Jersey's 1st District.
The victory means Democrats gain a new seat in the Assembly and incumbent Republican Assemblyman Sam Fiocchi won't be returning to the statehouse. Fiocchi's running mate, Jim Sauro, also lost his race.
Nearly $3 million was spent this year in the closely watched race, with much of the money coming from a super political action committee supporting Democrats.
Land is a former corrections officer who has never held elected office.