What is the sum of the weeks that games occured on october 21, 1974 and less than 50,623 fans attended?
CREATE TABLE table_39695 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Venue" text,
    "Attendance" real
)
SELECT SUM("Week") FROM table_39695 WHERE "Date" = 'october 21, 1974' AND "Attendance" < '50,623'
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 sum of the weeks that games occured on october 21, 1974 and less than 50,623 fans attended? ### Input: CREATE TABLE table_39695 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Venue" text,
    "Attendance" real
) ### Response: SELECT SUM("Week") FROM table_39695 WHERE "Date" = 'october 21, 1974' AND "Attendance" < '50,623'