If you are talking about immigration to the United States, the LPC clause came from a law that was passed in 1882, not in 1912.  The acronym “LPC” stands for “liable to become a public charge.”  The basic idea behind this clause was that immigrants should not be admitted to the United States if there was a likelihood that they would end up needing to be cared for by the state.  In other words, if they did not have enough money to support themselves, they might end up costing the government money and should not be allowed into the country.

In the years after the Nazis took Germany, this clause was used to exclude many Jews.  It was used to deny them visas.  Jews trying to flee Germany had often had their possessions taken from them by the Nazis.  Given the Depression and nativist feeling in the US, the US government was extremely reluctant to issue immigration visas.  Therefore, the LPC clause was used very often as a way to deny Jewish refugees entrance to the United States.

The connection between these two, then, is that the LPC clause was often used as a way to exclude Jews from Germany who wanted to seek refuge in the US.