A state senator is expected to announce he is running to replace Congressman Sean Duffy.  If so, Senator Tom Tiffany would become the first official candidate for the seat representing the state’s 7th Congressional District.  The Republican promised yesterday he was going to make a “special announcement.” Duffy is stepping down and there has been no indication when the special election to replace him might be held.  State Senator Jerry Petrowski announced he won’t be running Monday.