Berapa ons gula yang kita punya?
Meaning: How many ounces of sugar do we have?

You cannot translate 'ons' into 'ounce'.
Those are two different units.

'ons' = seratus gram = 100 grams.
https://kbbi.web.id/ons

'ounce' = 28.3 grams
https://en.wikipedia.org/wiki/Ounce