If the board have 4 5 6 7 of hearts.
James has J of hearts & 9 of clubs. Paul has K of hearts & 9 of hearts.
Who will win?
In no limit hold 'em the best 5 card combination of the 7 (2 in your hand, 5 on the board) make your hand. If multiple players have the same hand at showdown (two pair, straight, flush) the highest card or pair is looked at first, then the second highest card or pair etc.
In this case the king is higher than the jack heart and therefore wins.