CREATE TABLE table_28474 ("Character" TEXT, "Played by" TEXT, "Season 1" FLOAT, "Season 2" FLOAT, "Season 3" FLOAT, "Season 4" FLOAT, "First Appearance" TEXT)

What episode was the first appearance of the character who appears 7 times in season 4?
SELECT "First Appearance" FROM table_28474 WHERE "Season 4" = '7'
SELECT "First Appearance" FROM "table_28474" WHERE "Season 4" = '7'