Actualy Detroiters call these flats, not duplexes. If you had units side by side and each unit had a second floor(which would be bedrooms & a bathroom)they would be detached townhomes. Theres a unit downstairs and an identical unit upstairs in these buildings. The second door on the front(usually the left one)is a stairway that leads upstairs. The only time you will find units side by side is when you have a flat that has more than 2 units(4 & 8 family flats).
In some cases you might see just one door in the front, leading a person to think it's one big house. Most of those have stairs on the back porch leading up to the 2nd floor porch with the entrence usually through the kitchen. The back stairs like that are parallel to the structure similar to how a fire escape is. Just in case you might not have known, or just a little insight on homes like this for anyone in general that might not know.
