Table: us_congress_succession
Columns: district
vacator
reason_for_change
successor
date_successor_seated

Question: what is the total number of reasons for change where the date the successor was seated is june 8, 1876?
SQL: SELECT COUNT("reason_for_change") FROM us_congress_succession WHERE "date_successor_seated" = 'June 8, 1876'

Question: what is the reason for change where the date the successor was seated was july 28, 1876?
SQL: SELECT "reason_for_change" FROM us_congress_succession WHERE "date_successor_seated" = 'July 28, 1876'

Question: what is the district where the vacator is vacant?
SQL: SELECT "district" FROM us_congress_succession WHERE "vacator" = 'Vacant'