How many million U.S. viewers watched the episode with the production code 3x6004?
CREATE TABLE table_28725 (
    "No." real,
    "#" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "U.S. air date" text,
    "Production code" text,
    "U.S. viewers (million)" text
)
SELECT "U.S. viewers (million)" FROM table_28725 WHERE "Production code" = '3X6004'
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 the episode with the production code 3x6004? ### Input: CREATE TABLE table_28725 (
    "No." real,
    "#" real,
    "Title" text,
    "Directed by" text,
    "Written by" text,
    "U.S. air date" text,
    "Production code" text,
    "U.S. viewers (million)" text
) ### Response: SELECT "U.S. viewers (million)" FROM table_28725 WHERE "Production code" = '3X6004'