Dog bit me, but owners want me to house-sit again?

I agreed to house-sit for three days in October and verbally agreed to sit again over Thanksgiving after our first meet and greet. During the first night the dog bit me without provocation (we were sitting on the couch together watching TV) -- he bit hard enough to draw blood, but thankfully no stitches. The rest of the stay has been fine, albeit a little tense, especially since the dog needs to be carried up and down three flights of stairs for his morning, afternoon, and nightly walks.

My question is, how should I proceed with managing the expectation of the owners, especially if I decide that I am not up sitting this dog again? The second house-sitting session has not been finalized/booked through the Rover app (owners citing low money as the reason).

How do I proceed?