Well, if you want to split hairs, the bible does not necessarily say there were 13 at the last supper. According to the King James version, for example "[Jesus asked] Where is the guestchamber, where I shall eat the passover with my disciples?12 And he shall shew you a large upper room furnished: there make ready.13 And they went, and found as he had said unto them: and they made ready the passover.14 And when the hour was come, he sat down, and the twelve apostles with him". Notice that it initially says disciples and then later says the 12 sat with him. A perfectly reasonable interpretation is that there were more than 12 disciples present including all twelve apostles....