I have three coins, like the coins from Fifty-fifty. The first coin is a regular coin with heads and tails sides; the second coin has heads on both sides; the third coin has tails on both sides.

Two coins are chosen and flipped, with the third still shrouded in a pouch.
The results of the flips shows one head and one tail. What is the probability that the normal coin is the coin still in the pouch?