By definition, alloys are mixtures composed of two or or more elements, at least one of which is a metal. Alloys are important because their properties are often superior to those of their component elements. Sterling silver (92.5% silver and 7.5% copper) is harder and more durable than pure silver but still soft enough to be made into jewelry and tableware. Bronze is an alloy containing 7 parts of copper to 1 part of tin, and is harder than copper and more easily cast. Brass is an alloy of copper and zinc, and because it has a higher malleability than copper or zinc, it is often used to make brass instruments.
So to answer your question, whether or not a metal is more ductile than an alloy depends on what the alloy was made for. People in science and industry use different proportions of different elements to make alloys than suit their specific needs. It just so happens that in the case of brass, the alloy is more ductile than the copper and zinc from which it is made.