table: [['state (class)', 'vacator', 'reason for change', 'successor', 'date of successors formal installation'], ['new hampshire (2)', 'vacant', 'legislature failed to elect on time', 'john parker hale (r)', 'july 30 , 1855'], ['alabama (3)', 'vacant', 'legislature failed to elect on time', 'benjamin fitzpatrick (d)', 'november 26 , 1855'], ['pennsylvania (3)', 'vacant', 'legislature failed to elect on time', 'william bigler (d)', 'january 14 , 1856'], ['california (3)', 'vacant', 'legislature failed to elect on time', 'william m gwin (d)', 'january 13 , 1857'], ['indiana (3)', 'vacant', 'legislature failed to elect on time', 'graham n fitch (d)', 'february 4 , 1857']]
ref: there were 2 Successor who started in 1855 , which were Benjamin Fitzpatrick and John Parker Hale
template: there were 2 [ENT] who started in [ENT] which were [ENT] and [ENT]