MANCHESTER, N.H. – With urgency rising in their presidential nomination fight, the Democrats’ top presidential contenders clashed over experience and electability in a fiery debate Friday night that tested the strength of a new front-runner, former Midwestern mayor Pete Buttigieg, and struggling former Vice President Joe Biden. Biden, on the offensive throughout the high-stakes face-off, predicted he would “take a hit” in New Hampshire’s next-up primary election after a weak showing in Iowa.