What is the attendance of the game that has the opponent of The Nationals with a record of 68-51?
CREATE TABLE table_name_42 (
    attendance INTEGER,
    opponent VARCHAR,
    record VARCHAR
)
SELECT SUM(attendance) FROM table_name_42 WHERE opponent = "nationals" AND record = "68-51"
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 attendance of the game that has the opponent of The Nationals with a record of 68-51? ### Input: CREATE TABLE table_name_42 (
    attendance INTEGER,
    opponent VARCHAR,
    record VARCHAR
) ### Response: SELECT SUM(attendance) FROM table_name_42 WHERE opponent = "nationals" AND record = "68-51"