COLUMBUS, Ohio—On the eve of Ohio’s primary election, the unopposed Democrat, the Republican frontrunner, and his challenger for governor all made campaign stops in or near the Buckeye State’s capital city. On May 4, Republican candidate Vivek Ramaswamy received a standing ovation from about 150 people as he took the stage at a town hall meeting in Delaware County, just north of Columbus. If Ramaswamy wins the May 5 primary, he becomes the Republican nominee to face off against Dr. Amy Acton, a Democrat and the state’s former health director, in the Nov. 3 general election. She has no opponent in the primary....