Which center is which?

 From:  mickelsen
I have a drawing of an object with a circular hole in it. I want to position some things around the center of the hole, but when I try to use the center indicator (the little x that comes up labelled "center") there are two of them, very close together. Is there a way to find out what each center indicator applies to? I'm including the drawing. It might be easier to understand what I'm saying by looking at the drawing.