I think national polls at this point have very little meaning. However, since some were flaunting

the national polls as a "true indicator", instead of focusing on the states which actually determine who will be the nominee along will also be the President in the general election, here is the latest CNN/ORC Democratic National poll:

Hillary 55
Sanders 38

http://www.realclearpolitics.com/epolls/latest_polls/

As I said I don't hold much credibility in national polls at this stage, at least this one correlates with the state polls