One is sitting on a bench implies that one is on a bench.
This justifies what answer for what question? Q & A: 
Given the sentence "A man dressed in white sitting on a bench." is it true that "A man is on a bench."?
yes
One is sitting on a bench implies that one is on a bench.
This justifies what answer for what question? Q & A: 
user
Given the sentence "A man dressed in white sitting on a bench." is it true that "A man is on a bench."?
yes
assistant
One is sitting on a bench implies that one is on a bench.
This justifies what answer for what question? Q & A: 
Given the sentence "A man dressed in white sitting on a bench." is it true that "A man is on a bench."?
yes