CREATE TABLE table_20875 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

what is the date the successor seated because the person died august 17, 1954?
SELECT "Date successor seated" FROM table_20875 WHERE "Reason for change" = 'Died August 17, 1954'
SELECT "Date successor seated" FROM "table_20875" WHERE "Reason for change" = 'Died August 17, 1954'