A good rule of thumb to remember is that arteries always take oxygen rich blood away from the heart to the rest of the body and veins carry oxygen poor blood back to the heart. The only two circumstances this is not the case is the Umbilical and pulmonary vasculature. Pulmonary Arteries take oxygen poor blood away from the heart to the lungs to be oxygenated and this oxygenated blood returns to the heart via pulmonary veins.
