People who work in the software development field are responsible for developing and maintaining software products and systems. Skills and techniques used within software development are system design, programming, architecture and product management.
In a leadership position someone is responsible for a group of people, typically an organizational unit or the entire organization, depending on the size of the organization. Leaders are responsible and accountable for overseeing and guiding strategic activities, programs and managers who report to them. Just a few people in an organization are typically in a leadership role.