Have ran numbers but are they good enough to buy?

[Denton Beam]

Totally new to real estate investing. I have read lots of books and studied lots of numbers now it's time to move on something. My wife and I looked at a duplex this weekend so I ran the numbers. Seemed real easy, have punched them in tons of times (random houses on Zillow or Redfin). Well... maybe not so easy now that it's our money on the line. We are not sure if we are trying to talk ourselves out of the deal or if the numbers just aren't that great. The units are basically turn key would paint the inside and fix a couple minor things maybe 500 bucks. Tenant occupied in one unit for six more months other side is vacant. Anyway the place would cashflow at the asking price but the cash on cash ROI would only be 3% seems to be very low. Does that make this a horrible deal? The cap rate would be little over 6% witch does not seem to be to far off for the area.