Don’t let your mother tongue mislead you (if it is not English); “ton” in English is pronounced with the /ʌ/ sound (as “o” in “come” or “u” in “but”), similarly to “son” and “won”.
What may be even more confusing than the pronunciation is the fact that “ton” refers to the unit used in the US defined as 1 ton = 2,000 pounds = 907 kg. It can also refer to the ton used in the UK where 1 ton = 2,240 pounds = 1,016 kg, but which is no longer officially used (since 1985). If you want to refer to the so called “metric ton”, the word you are looking for is pronounced the same but is spelled “tonne”, i.e. 1 tonne = 1000 kg.