I think you're right, it was just Clinton. Mind you there's only 1794 living Rhodes scholars in the United States and one of them is a former President, so it increases your chance of becoming PoTuS from one in eighty million to one in 1794, and that's not bad.

Anyway, the point of all this isn't to pick on Rhodes Scholars but to point out the unreliability of child prodigies. In fact, Rhodes Scholars tend not to be the child-prodigy types at all. The selection process includes not just academics but also sport, social service and character requirements, completely inaccessible to the kid who has spent his entire childhood locked in a room being drilled on calculus. Rhodes Scholars tend to be smart but well-rounded, sociable and a bit conformist, exactly the sort of people who grow up to be politicians.

A Rhodes scholarship is no guarantee of success, but if I could buy shares in someone's life I'd put my money into Rhodes scholars rather than teenage prodigies.