Oil leak at the filter/ O Ring

Hey Guys. I have a leak that seems to be coming from behind the oil filter. I believe it is the O ring. I have referenced my service manual and can't get an understanding of how to replace this piecs. I am pretty sure it is an easy fix but could use some guildance. To get to the oil pump it reads that I would need to drop the oil pan? Is this necessary?

Its a stock 318 69 Coronet
Author: 68 Sat