Chinese makes ordinal numbers by prefixing 第 to the cardinal: 十九 (19) becomes 第十九 (19th). The ordinal then takes a measure word like 名 ('place/rank'), 届 ('session/edition'), 课 ('lesson'), 章 ('chapter').
culture
In post-1949 Chinese politics, 第十九 implicitly refers to the 第十九次全国代表大会, the 19th National Congress of the CCP, held in 2017. So in news and political contexts, 第十九 is often a shorthand reference to that era.
