12 games will not feel like a long time, the club has also played more than half of the 34 games this season with consistent performances so I don't think Leverkusen will be able to catch up unless Bayern Munich suffer a setback but that won't happen as long as they are still fighting hard with their star players Harry Kane this season has also contributed a lot to the team and he should be rewarded by winning the Bundesliga title.
It's not just about how long but the chances that Leverkusen have are almost very small to catch up on Bayern Munich's points because there are only 12 games left. I think Bayern Munich's chances to win the trophy again are quite open because so far their performance in the Bundesliga has been quite consistent. Leverkusen can return to the title race next season if they can maintain a much better consistency than this season. This season will also be a good moment for Harry Kane to get his first Bundesliga title so that it will be a much bigger motivation for him to give his best.