What is a leader?
But let's suppose there can be many types of leaders with different personalities and ideals. One condition must always be fulfilled, and that is that the followers must acknowledge the leader's competence and respect their abilities. On top of that, the followers must be willing to work with and trust their leader even if they don't completely understand or agree with them. However, it shouldn't be a relationship were the follower's opinions are completely disregarded, or where the followers can completely override their leader.
Styles of Leadership
However, I think these are somewhat inaccurate. Autocratic leadership would probably be the best choice in more monotonous work where the workers are low skill and the leader is the most knowledgeable of the group, while democratic leadership would be most effective if the members of the group were more or less equal. Delegative leadership would work best if all the members of the group were highly skilled.
Just as the type of leader needed for each situation differs, so does the qualities needed in a leader. For example, a politician needs to eloquent and persuasive and does not necessarily need a working understanding of the world. On the other hand, the CEO of a large company needs good social skills, and needs to be knowledgeable about their work.
Qualities of a Leader
I may not be able to be a politician or president, but I could very well be the CEO of a company, or some other position where your knowledge and skills are most important.