user: Question: What is the earliest year the World Junior Championships has 1500 m notes?
Columns: ['Year', 'Competition', 'Venue', 'Position', 'Notes']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2004.0, 'World Junior Championships', 'Grosseto , Italy', '4th (heats)', '800 m']
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Notes" = '1500 m' AND "Competition" = 'World Junior Championships';