By Caitlin Yilek Politics Reporter Caitlin Yilek is a politics reporter at CBSNews.com, based in Washington, D.C. She previously worked for the Washington Examiner and The Hill, and was a member of the 2022 Paul Miller Washington Reporting Fellowship with the National Press Foundation. Read Full Bio May 5, 2026 / 11:28 PM EDT / CBS News Add CBS News on Google Derek Merrin won the Republican primary in Ohio's 9th Congressional District on Tuesday, CBS News projected, setting up a rematch against longtime Democratic Rep. Marcy Kaptur in what's expected to be one of the most contested House races of the year.  Kaptur, the longest serving woman in Congress, has held the seat since 1983.  Merrin, a former state representative, tried to unseat Kaptur in 2024, but lost by about 2,400 votes — just above the threshold needed to trigger an automatic recount.…