How many episodes had an original air date with 5.1 million viewers
CREATE TABLE table_1379 (
    "No. in series" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "U.S. viewers (million)" text,
    "Original air date" text,
    "Production code" real
)
SELECT COUNT("Original air date") FROM table_1379 WHERE "U.S. viewers (million)" = '5.1'
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: How many episodes had an original air date with 5.1 million viewers ### Input: CREATE TABLE table_1379 (
    "No. in series" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "U.S. viewers (million)" text,
    "Original air date" text,
    "Production code" real
) ### Response: SELECT COUNT("Original air date") FROM table_1379 WHERE "U.S. viewers (million)" = '5.1'