There are a number of YouTube videos on removing the watermark which is generated on the free download version of PD.
Now I assume that you have some kind of other logo-watermark that needs to be removed, like the logo of a broadcast station? What you see other broadcasting parties do is blur the part of the screen where the watermark sits. Try and test the results of bluring (maybe in combination with coloring) and the various options available for that which suits best for you.
The other option is to zoom/crop the footage so that the watermark drops of the screen. Of course it depends pon where this watermark sits.
If the watermark is a piece of large text that say sits in the middle and covers the whole clip,then there as some (high school) options which involve making an as close as possible copy of the text and position that over the watermark. Then try blending. It is not easy and the results will not be perfect.
And.... it does not matter too much that people see that you have copied a clip from the competition, does it?