When hittite old kingdom , minoan eruption is the ubaid period in mesopotamia what is the copper age?
CREATE TABLE table_23537091_1 (
    copper_age VARCHAR,
    ubaid_period_in_mesopotamia VARCHAR
)
SELECT copper_age FROM table_23537091_1 WHERE ubaid_period_in_mesopotamia = "Hittite Old Kingdom , Minoan eruption"
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: When hittite old kingdom , minoan eruption is the ubaid period in mesopotamia what is the copper age? ### Input: CREATE TABLE table_23537091_1 (
    copper_age VARCHAR,
    ubaid_period_in_mesopotamia VARCHAR
) ### Response: SELECT copper_age FROM table_23537091_1 WHERE ubaid_period_in_mesopotamia = "Hittite Old Kingdom , Minoan eruption"