Technically speaking, I can beat Majora's Mask the quickest. I know that game like the back of my hand, and so I can speed through its four dungeons pretty fast and get up to the moon within 10-12 hours. However... I've never actually been able to do that. Problem is, I know the game TOO well, and I physically cannot complete the game anymore without getting all the masks. I just don't know how to do it, getting every single mask is just ingrained within me. So it takes me significantly longer to actually beat the game, even if I'm trying for a 3-heart run.
With that in mind, Ocarina of Time is the game I can actually finish the quickest. I can force myself to ignore all the sidequests, pieces of hearts, etc. and pull off a good 3-heart run with OoT. I also know it like the back of my hand, and so I know exactly what I can get away with. I've never actually sat down and timed myself, but I'd say somewhere around 12-14 hours.