Ghana incumbent President John Dramani Mahama won a new term with 50.7 percent of ballots cast in the West African state's election, the head of the Electoral Commission announced on Sunday."Based on the results, I declare President John Dramani Mahama president elect," Kwadwo Afari-Gyan told a news conference in the capital Accra.Mahama was up against main opposition challenger Nana Akufo-Addo, whose party said earlier on Sunday that it believed the election results were rigged.