It would be more probable if he got Viserion (if the Mad King is his father). Rhaegal would be Jon's, since his father was Rhaegar.

Color-wise, it makes more sense for Tyrion to have Rhaegal (he has one green eye? more matching light blonde hair to golden features on a dragon? (again, I'm judging by books, in the series light blonde just didn't go well with Peter Dinklage's skin colour, so they made it darker)) and Jon to have Viserion (after all Ghost was white and as white direwolves shouldn't exist he was special)...

But I'm more for the first option... Of course, I may be wrong xD