Veteran Democratic U.S. Rep. Marcy Kaptur is pulling away from congressional colleague Dennis Kucinich in the battle for a newly drawn Ohio congressional district.
Kaptur had a nearly 9-point lead with half the votes counted.
Kucinich made a strong showing in his home county, Cuyahoga, but was behind in critical Lorain County.
Toledo real estate agent Steve Kraus was holding a strong lead over Joseph Wurzelbacher on the Republican side of the race.
Wurzelbacher earned the nickname "Joe the Plumber" during the 2008 presidential election.
The winner of the Democratic primary is favored to win in the fall.
The newly drawn district connecting Cleveland to Toledo along the Lake Erie lakeshore tilts toward Democrats.