What is Tournament, when 2001 is '1R'?
CREATE TABLE table_50644 (
    "Tournament" text,
    "2000" text,
    "2001" text,
    "2002" text,
    "2003" text,
    "2004" text,
    "2005" text,
    "Career SR" text,
    "Career Win-Loss" text
)
SELECT "Tournament" FROM table_50644 WHERE "2001" = '1r'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is Tournament, when 2001 is '1R'? ### Input: CREATE TABLE table_50644 (
    "Tournament" text,
    "2000" text,
    "2001" text,
    "2002" text,
    "2003" text,
    "2004" text,
    "2005" text,
    "Career SR" text,
    "Career Win-Loss" text
) ### Response: SELECT "Tournament" FROM table_50644 WHERE "2001" = '1r'