CREATE TABLE table_2417445_4 (date_of_successors_taking_office VARCHAR, successor VARCHAR)

When rudolph kleberg (d) is the successor what is the date of successors taking office?
SELECT date_of_successors_taking_office FROM table_2417445_4 WHERE successor = "Rudolph Kleberg (D)"
SELECT "date_of_successors_taking_office" FROM "table_2417445_4" WHERE "Rudolph Kleberg (D)" = "successor"