Since you worked in two states for the same employer, you will only enter your W-2 one time.
The Federal portion will show the income that you earned throughout the whole year. Then, in the state section starting with Box 15, you will have two lines of information. One line will report your income shown for OH and the other line will show your income for NJ.
You received two paper W-2 forms because the form is not made to report more than one state at a time.
