I have two rubber hoses under my bike. 1 has a cap the other doesnt. T

I have two rubber hoses under my bike. 1 has a cap the other doesnt. T

I have two rubber hoses under my bike. 1 has a cap the other doesnt. They are bound together. My problem is just today I noticed after riding home from work the uncapped hose is leaking fuel . How do i fix this and what would be the cause of it?