Unless the water continues to rise above where it is supposed to (it eventually could reach the top of the overflow and go down into the bowl), then don't worry about it for now.
Some valve are designed with replaceable seals, some are not. If it is designed for a seal to be replaced, it's generally quicker, cheaper, and easier to just do that. Otherwise, you will need to replace the entire valve assembly. Note, when you do that, it's a good idea to change the hose between the wall shutoff and the valve in the tank. If that is rigid, you can reuse it.
You DO want to place the end of the hose into the bracket above the overflow tube. Without that directing some water down the overflow into the bowl, the bowl itself won't be filled to the design level and that can sometimes have a very negative effect on the energy of the flush.
One way to test if the bowl is full is to first note where it is, then, slowly add water into the bowl. At some point, it will stop rising. If that new water height is higher AND stays there after a delay, that's where it is designed to be, and putting the hose where it's supposed to be should fix it.