The relevant information is: Charles Ellis Schumer (/ umr /; born November 23, 1950) is an American politician of the Democratic Party serving as the senior United States Senator from New York, a seat he was first elected to in 1998.
This justifies what answer for what question? Q & A:
Passage: Charles Ellis Schumer (/ umr /; born November 23, 1950) is an American politician of the Democratic Party serving as the senior United States Senator from New York, a seat he was first elected to in 1998. Since 2017 he also is the Senate Minority Leader. He first defeated three-term Republican incumbent Al D'Amato 55 % to 44 % before being reelected in 2004 with 71 % of the vote, in 2010 with 66 % of the vote, and in 2016 with 70 % of the vote.

Question: Based on this passage, who is the senior senator from new york?
Charles Ellis Schumer