I did find this on funtrivia.com when googling the question of dual champions in same city
Here's by state:
2004 - New England Patriots & Boston Red Sox
2003 - Tampa Bay Buccaneers & Florida Marlins
1989 - San Francisco 49'ers & Oakland A's
The only other city wins for the Superbowl and World Series were Pittsburgh in 1979, and then the NY Jets and NY Mets in 1969.
Here's by state:
2004 - New England Patriots & Boston Red Sox
2003 - Tampa Bay Buccaneers & Florida Marlins
1989 - San Francisco 49'ers & Oakland A's
The only other city wins for the Superbowl and World Series were Pittsburgh in 1979, and then the NY Jets and NY Mets in 1969.