"I am also standing by this door."
Translation:Én is ennél az ajtónál állok.
Whether you use definite conjugation or not is a matter of whether the direct object is definite, i.e. the object in accusative case, i.e. the object with a -t suffix. Since áll is (pretty much) completely intransitive, you won't have much of a chance encountering állom.
But you can paint this door if you like: "Én is ezt az ajtót festem." -t suffix and definite conjugation, there you go.