CREATE TABLE table_name_37 (interregnum_ended VARCHAR(255), count_palatine_of_saxony VARCHAR(255))
What is the Interregnum ended for Count Palatine of Saxony of frederick augustus i, elector of saxony?
    
SQL: SELECT interregnum_ended FROM table_name_37 WHERE count_palatine_of_saxony = "frederick augustus i, elector of saxony"