How to filter duplicates with swapping column names in pandas

Question

I have a pd.Dataframe that looks like this:

   a_p1  a_x1  a_x2  b_p1  b_x1  b_x2
1   0.0   0.0   0.0   1.0  -1.0   0.0
2   1.0  -1.0   0.0   0.0   0.0   0.0