Here's how the parties did in each host state

[elleng]

between the previous election and the election of the convention year.

Year Convention site Party Win in previous election? Convention year?
2004 New York Republican No No
2004 Boston Democratic Yes Yes
2008 St. Paul Republican No No
2008 Denver Democratic No Yes
2012 Tampa Republican No No
2012 Charlotte Democratic Yes No

In four of the last six examples, the party didn't win the state in which the convention was held. In only one case — Denver, 2008 — did the party win a state it had lost in the previous cycle.

http://www.washingtonpost.com/blogs/the-fix/wp/2014/06/26/dallas-vs-cleveland-the-battle-to-host-the-2016-republican-convention/