CREATE TABLE table_18795125_6 (date_of_vacancy VARCHAR2, position_in_table VARCHAR2)

At what date did the 23rd manager vacate the position?
SELECT date_of_vacancy FROM table_18795125_6 WHERE position_in_table = "23rd"
SELECT "date_of_vacancy" FROM "table_18795125_6" WHERE "23rd" = "position_in_table"