CREATE TABLE table_46732 ("Model" TEXT, "Memory  (  RAM  ) " TEXT, "Storage  (  flash  ) " TEXT, "Operating system version" TEXT, "Memory card" TEXT, "Weight ,  dimensions" TEXT, "Retail availability" TEXT)

Which operating system has 1GB (mobile ddr) memory (RAM)?
SELECT "Operating system version" FROM table_46732 WHERE "Memory ( RAM )" = '1gb (mobile ddr)'
SELECT "Operating system version" FROM "table_46732" WHERE "Memory ( RAM )" = '1gb (mobile ddr)'