You know at the Church of Cane Bay a Huddle is a two or three people coming together to help each other Give, Grow and Go. We don't generally use the language "Huddle Leader".
However, the huddle relationship can vary depending on the spiritual history of those meeting. We would encourage you to know that, if the person you are meeting with is significantly younger in their faith than you, to have this relationship be more like big brother little brother, or even parent to child. What does this mean?
As you interact over the Bible together lean toward teaching instead of assuming they will self discover.
This follows Jesus command when we come alongside a new believer we first help them be baptized, and then it says, "and teach them to obey everything I have commanded you." MT 28:20a
The goal in this relationship is isn encouraging them to be learning to feed themselves the Bible. You can see in 1 John 2:27 and Hebrews 8:11 that a believer should be able to be taught by God Himself. So the answer to how long is, until they can read the Bible themselves, know what God wants them to learn, be changed how God directed, and talk to Him about it. One metric can be that they regularly and genuinely SOAP with joy.
As this is happening the relationship shifts gradually to a sibling relationship.