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_name_27 (operating_system_version VARCHAR, memory___ram__ VARCHAR)

### Question ###
Which operating system has 1GB (mobile ddr) memory (RAM)?

### Accurate SQL ###

SELECT operating_system_version FROM table_name_27 WHERE memory___ram__ = "1gb (mobile ddr)"