CREATE TABLE table_name_78 (interregnum_ended VARCHAR2, duration VARCHAR2)

What is the Interregnum ended for the person with a Duration of 3 months, 6 days?
SELECT interregnum_ended FROM table_name_78 WHERE duration = "3 months, 6 days"
SELECT "interregnum_ended" FROM "table_name_78" WHERE "3 months, 6 days" = "duration"