Yes, Dan, in 1954, the late conservative William "Bill" Cramer of St. Petersburg became FL's first Republican congressman since Reconstruction. HE lost the 1970 Senate general election to the late Democrat Lawton Chiles and his House seat was forfeited as well.
Tampa went Democrat for years, but St. Petersburg and Pinellas were heavily Republican. I understand that Albert A. Gore, Jr., who celebrates his 57th birthday today, actually carried Pinellas in 2000. So it is now a liberal but nominally Republican county, with a very corrupt machine. Why the popular former county commissioner and "swamp judge" (as Michael Savage calls him) George W. Greer is the "head" of this machine remains something of a mystery.
A lot of Michiganders moved to both areas, and also Naples/Sarasota/Lakeland/.