All you have provided is a bunch of numbers on paper. Without knowing a lot more about the property, I can't tell you what I would pay for it or if I would even buy it. Where is it located? How old is it? What condition is it in? What's the neighborhood like? What's the vacancy in the neighborhood? Are rents in the area increasing, decreasing, or stagnant? What have other duplexes in the area sold for recently and are they comparable? What employers are nearby? Is the property close to transit? Are both units occupied? How long have the tenants been there? Are the utilities separately metered? Does the duplex conform to existing zoning? Are there garages, carports, or other off-street parking? Are there common laundry facilities, does each unit have its own, or do the tenants have to find a laundromat? Are the floorplans desirable to the rental market? How many bedrooms/baths in each unit? How much does the landlord pay for common area maintenance and utilities?
I could go on for half a page, but you get the idea. You are not buying a share of stock. A duplex is not a piece of paper. It's an assemblage of moving parts, all of which must be understood before deciding to buy or what price to pay. If you buy based on paper numbers, you will end up with a bunch of problems you could not have anticipated.