CREATE TABLE table_24400 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

When john w. leftwich (uu) is the successor what is the date the successor was seated?
SELECT "Date successor seated" FROM table_24400 WHERE "Successor" = 'John W. Leftwich (UU)'
SELECT "Date successor seated" FROM "table_24400" WHERE "Successor" = 'John W. Leftwich (UU)'