No, winning a debate does not mean that one has found truth. Winning a debate means only that the person has argued their position better than the other person. Perhaps with a stronger opponent, or with more information available to either or both sides, the outcome of the debate would have been different. Debate is only an art form.
If you win a debate, a few things happen. 1. You beat your opponent. 2. You have found useful facts and used them to your advantage.
But no. New facts are always on the rise, and new theories are always being made. In fact, winning one debate probably means your opponent was incompetent at debating, so you will need to find someone who can debate better.