EXCLUSIVE JUST LISTED  Spacious, Newly Renovated 1-Bd. Co-op w/ Doormen & Pool    A spacious and bight corner unit, this 1-bedroom, 1-bath apartment is at The Presidential (601 Kappock Street), a postwar co-op building with part-time doormen in the Spuyten Duyvil section of Riverdale. It is freshly renovated and enjoys open, leafy views.    Features include: an entry vestibule; living room with northern picture window; dining foyer; renovated eat-in kitchen with brand-new appliances (Whirlpool dishwasher, Frigidaire 6-burner stove and refrigerator); windowed and renovated bathroom; newly installed oak hardwood floors; new through-the-wall air conditioners; north and east exposures; 5th floor. Monthly Maintenance $805.20.    Outdoor swimming pool and children's playground in complex. The building has a bicycle room and storage facilities.    Dogs okay (but no aggressive breeds or dogs over 70 pounds).    Close to shops, parks, Metro-North trains and express buses to Manhattan's East and West Sides.