If the duck goes after the dog continuously, I'd say the dog was a saint to hold out this long. Please don't allow the duck to keep harassing the dog. It cruel to a old blind dog, and the duck is gonna run out of luck one of these times. I would try and flush his wound with saline solution and then put some neosporin on it. I know they do that for chickens - don't know if ducks are sensitive to those products. Make sure he isn't out where flies could leave eggs on him- to hatch into maggots. - until it looks healed up. If he would develop symptoms like no appetite, swelling.pus discharge, lethargy, he would probably need an antibiotic. Hopefully wiser souls will be adding their input soon.
