Colonel Fairbairn certainly thought so. He and his group of Chinese bada$$es met knife-wielding assailants often when cleaning up Shanghai. His advice - shoot for the belly. It doesn't kill quickly but they find something else to think about. That'd be Fairbairn second from the left. I wouldn't care to mess with these guys.
Of course, there isn't really any part of the human body, even the fingertip, that's "non-lethal". My advice would be to shoot their hats off, twirl the gun a few times, blow the smoke out of the barrel, and re-holster. Assuming it's Saturday morning and your assailant happens to be a bad guy wearing a black hat.
After talking with a Korean War combat surgeon, I decided that a shot to the bladder is a good way to stop someone in their tracks. Making the second shot becomes a bit more difficult though since the writhing agony assailant will likely be in a fetal curl and spinning.
Learn something new every day!