Neither won, nor lost.
There have been several times when someone, usually Tom, corrected my memory on a point or showed me where something I thought to be true was not. Vice versa, I've corrected other's mis-assertions a few times. I would not count them as victories or losses.
However, mainly what happens here is a discussion of opinion. If you are going for some kind of victory when you are talking about your beliefs and your opponents beliefs, then you are doing something wrong.
Sometimes (rarely) I even get to have a discussion about my own opinions (rather than the opinions of the leftists).