WASHINGTON -- Democrats gained their first challenger to Sen. Rob Portman (R-Ohio) Thursday, with 30-year-old P.G. Sittenfeld, a member of the Cincinnati City Council, jumping into the 2016 race and betting that Ohioans want someone new in the stodgy Senate. "I believe that I have got the right kind of experience," Sittenfeld told The Huffington Post in an interview Thursday morning.