By Katie GlueckIn Ohio, Sen. Sherrod Brown, a longtime champion of working-class voters, was toppled by a rich Republican former car dealer.In Washington, President Joe Biden — who won the Democratic nomination four years ago with the help of blue-collar voters — must now hand back power to Republicans and surrender leadership of a party increasingly dominated by highly educated voters.And in Pennsylvania, Sen. Bob Casey, whose family name has for years been synonymous with white working-class D