Table: successor_info
Columns: district
vacator
reason_for_change
successor
date_successor_seated

Question: Name the successor for not filled this congress
SQL: SELECT "successor" FROM successor_info WHERE "date_successor_seated" = 'Not filled this congress'

Question: Name the district for  rep. warren r. davis died during previous congress
SQL: SELECT "district" FROM successor_info WHERE "reason_for_change" = 'Rep. Warren R. Davis died during previous congress'

Question: Name the total number of reason for change for not filled this congress
SQL: SELECT COUNT("reason_for_change") FROM successor_info WHERE "date_successor_seated" = 'Not filled this congress'

Question: Name the vacator for resigned february 26, 1836 because of ill health
SQL: SELECT "vacator" FROM successor_info WHERE "reason_for_change" = 'Resigned February 26, 1836 because of ill health'