I've got to say, I'm shocked! I don't think that this poll will be indicative though, if the election were held today, Hillary would more than likely win against Ryan. I think there is an over sample of republicans here.
Barack Obama: 49%
Mitt Romney: 45%
Yep, looks like a slight over sample of republicans....
If you look at the later questions, this poll over-samples Republicans/conservatives and independents, along with whites (90%!) and older people.
OK, you're right about the first part, but remember, Wisconsin is 83% white (just as white as Minnesota). Its not at all surprising that the electorate would be 90% white, especially for a mid-term.