12-gauge is fine. But 10-gauge is overkill in a good way.

Yes, 12-gauge will handle 15 amps at 50 feet for a table saw. Voltage drop at that distance is around 3–4%, which is well within safe limits. The saw will start and run fine.

But if you’re buying a new cord, 10-gauge isn’t a bad choice either. It drops less voltage (maybe 2% instead of 4%), which means the motor sees full power more consistently. And if you ever upgrade to a bigger saw or run it 100 feet, that 10-gauge is already ready.

I wouldn’t stress it. 12-gauge works. 10-gauge just works a little better and costs a little more. Either won’t burn your shop down.