just come back after you've gotten four gym badges
in the peatalberg gym he is the leader
The 14th gym leader is the 14th gym you challenge, and there really isn't an order. However, in chronological order, the 14th gym is the gym in Saffron City, with Sabrina as the gym leader.
simply go back to petalburg where your father is gym leader and you must challenge him
The only way to get a gym badge is to challenge the corresponding gym leader and win.
Go down to oreburgh mine and talk to the gym leader he will run off now go to oreburgh city and go into gym that gym leader will challenge you.
Beat the 7th gym leader which is near cinnabar island and talk to the 8th gym leader which is on cinnabar island and he is going to go back to the gym to wait for you to challenge him.
You can challenge the petalburg gym after you beat fire type gym leader in lavaridge town.
You have to go to the contest hall and she will be there. Then she leaves and now you can challenge her at the gym.
You go inside the gym, and there is usually a maze you have to get through to be able to fight the gym leader. After that, you just walk up to the leader.
walk into the gym challenge the gym leader... o and it helps to have a few Pokemon
I don't think you can re challenge a gym leader you have already beaten in Pokemon white.
She is the 2nd gym leader ;))