[['state (class)', 'vacator', 'reason for change', 'successor', "date of successor 's formal installation"], ['south carolina (3)', 'olin d johnston (d)', 'died april 18 , 1965', 'donald s russell (d)', 'april 22 , 1965'], ['south carolina (3)', 'donald s russell (d)', 'successor elected november 8 , 1965', 'ernest hollings (d)', 'november 9 , 1965'], ['virginia (1)', 'harry f byrd (d)', 'resigned november 10 , 1965', 'harry f byrd , jr (d)', 'november 12 , 1965'], ['michigan (2)', 'patrick v mcnamara (d)', 'died april 30 , 1966', 'robert p griffin (r)', 'may 11 , 1966'], ['virginia (2)', 'a willis robertson (d)', 'resigned december 30 , 1966', 'william b spong , jr (d)', 'december 31 , 1966'], ['tennessee (2)', 'ross bass (d)', 'resigned january 2 , 1967', 'vacant', 'not filled this term']]
Donald S Russell and Harry F Byrd were in Congress during the same month
[ENT] and [ENT] were in [ENT] during the same month