I'm not entirely sure which 'Johnny' specifically in 'Pulp Fiction' you are referring to. There are a lot of characters in that movie, and if it's a relatively minor character named Johnny, it might not be immediately obvious without more context. It could be a character who has a brief appearance or is part of a sub - plot that we don't recall right away.
The movie 'Pulp Fiction' has a large cast of characters. While there may be a Johnny in it, it's not one of the characters that come to mind immediately like Vincent Vega or Jules Winnfield. It could be a name that is mentioned in passing or a character that has a very specific role within the movie's convoluted plot structure. Without further details, it's difficult to be more precise about who Johnny is.
In 'Pulp Fiction', Johnny is not one of the most prominently known main characters. However, there could be minor characters named Johnny in the complex web of the movie's narrative. Without more specific information, it's hard to say exactly who this 'Johnny' refers to in relation to the movie.