How many million U.S. viewers watched episode number 6 in the series?
CREATE TABLE table_27981 (
    "No. in series" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "Original air date" text,
    "Production code" text,
    "U.S. viewers (million)" text
)
SELECT "U.S. viewers (million)" FROM table_27981 WHERE "No. in series" = '6'
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 million U.S. viewers watched episode number 6 in the series? ### Input: CREATE TABLE table_27981 (
    "No. in series" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "Original air date" text,
    "Production code" text,
    "U.S. viewers (million)" text
) ### Response: SELECT "U.S. viewers (million)" FROM table_27981 WHERE "No. in series" = '6'