Q: Context: Pressure increased across the country. The related civil suit was heard in federal district court and, on June 4, 1956, the court ruled in Browder v. Gayle (1956) that Alabama's racial segregation laws for buses were unconstitutional. As the state appealed the decision, the boycott continued. The case moved on to the United States Supreme Court. On November 13, 1956, the Supreme Court upheld the district court's ruling, ruling that segregation on public buses and transportation was against the law.

Question: when did the supreme court ruled that bus segregation was unconstitutional? Let's give stream of consciousness first:
The relevant sentence in the passage is: On November 13, 1956, the Supreme Court upheld the district court's ruling, ruling that segregation on public buses and transportation was against the law. Therefore, the final answer is On November 13 , 1956.