Rab Acha, the son of Ravina [Rashi explains he was a Kohen], sent to him Rav Ashi that he had taken coins for the redemption of the firstborn, [Baba Batra (60a)]. And it seems that he is a Kohen. [And so Rashi explains in his commentary]:
Seder_HaDorot,_Tanaim_and_Amoraim.347:1