CREATE TABLE table_204_561 (id DECIMAL, "fence" DECIMAL, "name" TEXT, "jockey" TEXT, "age" DECIMAL, "handicap  ( st-lb ) " TEXT, "starting price" TEXT, "fate" TEXT)

what is the total age of what a myth and rough tweed ?
SELECT SUM("age") FROM table_204_561 WHERE "name" IN ('what a myth', 'rough tweed')
SELECT SUM("age") FROM "table_204_561" WHERE "name" IN ('what a myth', 'rough tweed')