Where to find duplexes?

[Ricky Stafford]

Hi.

I am interested at swooping up a vacation rental style investment in the shape of a duplex that would also double as a long term rental should it be necessary. I would live in one side. In most markets I have looked, there are few, if any, duplexes for sale. Zillow makes it notoriously difficult to find duplexes. The only way I have found any are by using the keyword "duplex" or "multifamily". 

I've checked Austin, TX and Raleigh, NC as they are both hotbeds for tech which is kind of what I am looking for, with Austin being the more general-purpose market (but also more expensive).

Any ideas on where to start? Thanks