What happens if two forces of unequal strength attacks the same province?
There are lots of different versions of the rules, so it is hard to give an exact quote and page reference, but they all agree on the resolution of this. The version I found says "A unit moves with its own strength combined with all of its valid supports. Unless it is opposed by a unit that is equally or better supported, it can complete its move." In this case Bohemia was opposed by a better supported unit, so it cannot complete its move and stays in Bohemia.

So in the case that two or more attacks occur on the same province, and one is stronger than all the others as well as being stronger than the existing defense, the strongest attack succeeds and the others all fail. Any units participating in those attacks remain where they were (unless they are dislodged by a different attack on their own province) and any units that started in the attacked province are dislodged and will need to retreat. You can only be dislodged from the province that you started the turn in.

If there are multiple attacks on the same province, and there are two or more attacks tied for the strongest (or tied with the existing defense), then all the attacks fail. This can result in an unsupported defender holding a province against two supported attacks as long as the supported attacks are of equal strength.