Compared to the rest of the DFW Metroplex market, the Duncanville submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 3 listings have been listed, which means leases most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,660 sqft. Most buildings in this region are around 1 floors. Most buildings in this area were built in 2003 and are Class B.