At least in my dialect/accent of English
I’m sure that’s a regional way to pronounce it. I’ve lived in the south (North Carolina) my whole life and I’ve always heard and pronounced it as the same sound as caught, or aught.
In fact, according to The American Heritage® Dictionary of the English Language, both aught and ought have the same pronunciation.
Weird. It may sound subtle ( another weird word), but my mouth is definitely doing different things. Ought has a definite diphthong whereas aught may have one, but much more slight and with a more closed mouth.
Languages are weird.
Edit: aught is likely grown out of naught! I mean, that obviously makes sense, just never actually thought about it.