CREATE TABLE table_name_93 (year INTEGER, competition VARCHAR(255), category VARCHAR(255), beer_name VARCHAR(255), prize VARCHAR(255))
What year did maggs magnificent mild win a gold medal in the mild and porter category at the siba south east region beer competition?
    
SQL: SELECT AVG(year) FROM table_name_93 WHERE beer_name = "maggs magnificent mild" AND prize = "gold medal" AND category = "mild and porter" AND competition = "siba south east region beer competition"