What is the surface on 21 june 1993?
CREATE TABLE table_77181 (
    "Outcome" text,
    "Date" text,
    "Championship" text,
    "Surface" text,
    "Opponent" text,
    "Score" text
)
SELECT "Surface" FROM table_77181 WHERE "Date" = '21 june 1993'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the surface on 21 june 1993? ### Input: CREATE TABLE table_77181 (
    "Outcome" text,
    "Date" text,
    "Championship" text,
    "Surface" text,
    "Opponent" text,
    "Score" text
) ### Response: SELECT "Surface" FROM table_77181 WHERE "Date" = '21 june 1993'