Long (Pole/Poll/Pull)?

When you’re indicating that something is the critical path that causes the whole project to take a long time, which one is it?

1. Long Pole
2. Long Poll
3. Long Pull

I actually find various sources when I look it up on google that contradict each other.

• https://www.macmillandictionary.com/us/dictionary/american/a-long-pull
• https://devblogs.microsoft.com/oldnewthing/20080805-00/?p=21373