CREATE TABLE table_3903 ("Standard" TEXT, "Date" TEXT, "CO  ( g/kWh ) " TEXT, "NO x  ( g/kWh ) " TEXT, "HC  ( g/kWh ) " TEXT, "PM  ( g/kWh ) " TEXT)

What's the HC for the standard with NO x of 7.0 g/kWh?
SELECT "HC (g/kWh)" FROM table_3903 WHERE "NO x (g/kWh)" = '7.0'
SELECT "HC (g/kWh)" FROM "table_3903" WHERE "NO x (g/kWh)" = '7.0'