How does this work exactly?

Look I know this is about women's basketball so no one cares, but I couldn't help but wonder while I watched the highlights last night on SportsCenter: how exactly does the NCAA women's basketball tournament get away with letting a 9 seed host a 1 seed in the 2nd round? How did Duke not get to host being a 1 seed? This type of thing would never happen in the men's tournament and the advantage for Michigan St is pretty clear. I guess one of the reasons that women's basketball isn't taken as seriously.