What is the opening date of the musical at the adelphi theatre?
CREATE TABLE table_name_6 (
    opening_date VARCHAR,
    classification VARCHAR,
    theatre VARCHAR
)
SELECT opening_date FROM table_name_6 WHERE classification = "musical" AND theatre = "adelphi theatre"
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 opening date of the musical at the adelphi theatre? ### Input: CREATE TABLE table_name_6 (
    opening_date VARCHAR,
    classification VARCHAR,
    theatre VARCHAR
) ### Response: SELECT opening_date FROM table_name_6 WHERE classification = "musical" AND theatre = "adelphi theatre"