
A 13 week old puppy will not be house trained. He won't ahve much in the way of voluntary bladder control until about 5 months.
When you encourage and take him outside eh goes there as he happens to be there, the times he has an accident he feels a sudden need to go and does, where he happens to be, as he sees no reason not to.
This is just like toddlers who are playing and then pee their pants, even though they only recently went.
As th training progresses and his bladder control increases the penny will drop that outside and only outside is the place to go.
The puppy training pads will only set you back, because in effect your telling him that inside is also the place to go.
What are you cleaning accidents up with? If it is disinfectant or any product with pine or ammonia it will only encourage him to go there again. A solution of biological washing powder/liquid will remove the faint traces that will attract him to that are.
The more accidents he has indoors the longer the house training association will take.
He needs to be watched like a hawk, and when you can't then he needs restricting to a small cleanable area. this will have two effects, limiting the accident areas and encouraging him not to go as he won't want to soil his bed and the immediate vicinity.