This is not the first match in which Dortmund has acted in this way against a strong opponent, they did something similar in the match against Newcastle. For Dortmund, an away draw is a completely acceptable result, but for Bayer it is a loss of very important points, now Bayern will almost certainly be able to take advantage of these and get ahead of them, although if they win they will be equal on points, but Bayern will have a better goal difference.
If we talk about the theoretical situation, Bayer still have an advantage - firstly, for Bayern to catch up with them, they still have to win the game in hand. Secondly, even if Bayern wins, the teams will have an equal number of points, but the remaining head-to-head game will be on Bayer's field where they can tip the scales in their favor. But these are theoretical considerations, it is clear that Bayern actually remains a very big favorite.