I’m trying to visualise how he got the whole length of the leash onto the table and then got it to stay on the table. The human end of the leash would be dragging on the ground and would have a tendency to remain on the ground when he jumped up.

For the whole length of the leash to stay on the table he would have to either drag it up paw over paw (or jaw over paw) or he could walk around on the table long enough and far enough that the leash followed him up there. It’s a long leash and a small table. I’m not seeing it.