user: Question: Which operating system has 1GB (mobile DDR) memory (RAM)?
Columns: ['Model', 'Memory ( RAM )', 'Storage ( flash )', 'Operating system version', 'Memory card', 'Weight, dimensions', 'Retail availability']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['770', '64MB', '128MB', 'OS2005/6, OS2007/8HE', '1 RS-MMC slot II', '230g, 141x79x19mm', 'November 2005']
SQL:

assistant: SELECT "Operating system version" FROM "Table" WHERE "Memory ( RAM )" = '1GB (mobile DDR)';