Fifteen Democrats have served as President under 16 administrations: the first was seventh President Andrew Jackson, who served from 1829 to 1837; Grover Cleveland served two nonconsecutive terms from 1885 to 1889 and 1893 to 1897; and is thus counted twice (as the 22nd and 24th President). The most recent was the 44th President Barack Obama, who held the office from 2009 to 2017.

Based on this passage, who was the first president identified as a democrat? Let's give stream of consciousness first:
To answer this question, we should know that: Fifteen Democrats have served as President under 16 administrations: the first was seventh President Andrew Jackson, who served from 1829 to 1837; Grover Cleveland served two nonconsecutive terms from 1885 to 1889 and 1893 to 1897; and is thus counted twice (as the 22nd and 24th President).
So, the final answer is seventh President Andrew Jackson.