SELECT "Date" FROM table_57968 WHERE "Home team score" = '13.13 (91)'
What day does the home side score 13.13 (91)?
CREATE TABLE table_57968 (
    "Home team" text,
    "Home team score" text,
    "Away team" text,
    "Away team score" text,
    "Venue" text,
    "Crowd" real,
    "Date" text
)