What former President defended the kidnapped slaves from the Spanish ship La Amistad?

United States v. Libellants and Claimants of the Schooner Amistad, 40 US 518 (1841)

None. John Quincy Adams was supposed to argue on behalf of the kidnapped Africans who mutinied aboard La Amistad, but was taken ill at the last moment and was unable to attend. Roger Sherman Baldwin (no relation to Justice Henry Baldwin), a prominent attorney who defended the 53 men at their trial, delivered oral arguments in Adams' place.