I don't think you have to mention the position if it's the first one.
So I think it's just called Diphenylmethanon
Benzophenone https://www.ncbi.nlm.nih.gov/books/NBK373188/#:~:text=Benzophenone%20is%20used%20as%20a,pharmaceuticals%20(HSDB%2C%202010).
When I search for Diphenylmethanone the first thing that comes up is Benzophenone (I found this under Benzophenone)
