How big in metric terms is the unit that has a ratio of 1/20?
CREATE TABLE table_39049 (
    "Unit" text,
    "Russian" text,
    "Translation" text,
    "Ratio" text,
    "Cubic inches (exact)" text,
    "Metric value" text,
    "Imperial" text,
    "US Customary" text
)
SELECT "Metric value" FROM table_39049 WHERE "Ratio" = '1/20'
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 big in metric terms is the unit that has a ratio of 1/20? ### Input: CREATE TABLE table_39049 (
    "Unit" text,
    "Russian" text,
    "Translation" text,
    "Ratio" text,
    "Cubic inches (exact)" text,
    "Metric value" text,
    "Imperial" text,
    "US Customary" text
) ### Response: SELECT "Metric value" FROM table_39049 WHERE "Ratio" = '1/20'