Name the total number of overall for defensive tackle
CREATE TABLE table_71787 (
    "Round" real,
    "Pick #" real,
    "Overall" real,
    "Name" text,
    "Position" text,
    "College" text
)
SELECT COUNT("Overall") FROM table_71787 WHERE "Position" = 'defensive tackle'
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: Name the total number of overall for defensive tackle ### Input: CREATE TABLE table_71787 (
    "Round" real,
    "Pick #" real,
    "Overall" real,
    "Name" text,
    "Position" text,
    "College" text
) ### Response: SELECT COUNT("Overall") FROM table_71787 WHERE "Position" = 'defensive tackle'