Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_23537091_1 (copper_age VARCHAR, ubaid_period_in_mesopotamia VARCHAR)

### Question ###
When hittite old kingdom , minoan eruption is the  ubaid period in mesopotamia what is the copper age?

### Accurate SQL ###

SELECT copper_age FROM table_23537091_1 WHERE ubaid_period_in_mesopotamia = "Hittite Old Kingdom , Minoan eruption"