What is the difference between pg and pg 13 ratings?

The only verified source supplied is a Wikipedia article on film censorship in the Republic of Ireland, which discusses the history and structure of the Irish Film Classification Office and its legislation. That article does not mention the MPAA rating system, nor does it provide any details about the PG or PG‑13 categories. Therefore, based on the available evidence, I cannot offer a difference between PG and PG‑13 ratings.