Who Will Be the Dragon's Apprentice?

A dragon and a rival wizard duel every ten years to see who is stronger. Each time the duel ends in a draw. Realizing they’re growing too old to continue fighting with one another they make a wager. Each must pick and train an apprentice. In ten years time the apprentices will duel instead. There is a catch. The dragon must pick a human to be his apprentice, while the wizard must pick a dragon to be his apprentice.