For sword and shield or sword and buckler duels, a one-handed sword is usually the better choice for a beginner. It is lighter, easier to control, and allows the shield to provide additional defense. A longsword is suitable for fighters who specifically want to train for the longsword duel category, but it requires two-handed control, good distance management, and more developed defensive technique.
Swords are generally better suited to duels than mass battles. In melees, sword blades may be heavily damaged by repeated collisions with polearms and axes. A beginner preparing for group combat may prefer a basic falchion, mace, or axe, especially if their fighting style includes close-range wrestling.