What is the attendance for the game against the Kansas City Chiefs earlier than week 13?
CREATE TABLE table_78612 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Attendance" real
)
SELECT AVG("Attendance") FROM table_78612 WHERE "Opponent" = 'kansas city chiefs' AND "Week" < '13'
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 for the game against the Kansas City Chiefs earlier than week 13? ### Input: CREATE TABLE table_78612 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Attendance" real
) ### Response: SELECT AVG("Attendance") FROM table_78612 WHERE "Opponent" = 'kansas city chiefs' AND "Week" < '13'