Without a doubt.. SPONGEBOB.
They are two different shows though.. Dora is directed towards pre-schoolers and REALLY young people (which is why it was always on Nick Jr.) and comparing it to a show that was still for younger people, but not as young as the ones who watch Dora.
Either way.. I'd rather watch the always-epic Spongebob than Dora where she asks a question and then does a 5 second pause.