user: Question: Name the total number of NGC number for sagittarius and diffuse nebula with declination of °02′
Columns: ['NGC number', 'Object type', 'Constellation', 'Right ascension ( J2000 )', 'Declination ( J2000 )']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [6514.0, 'Diffuse nebula', 'Sagittarius', '18h02m23s', '°02′']
SQL:

assistant: SELECT COUNT("NGC number") FROM "Table" WHERE "Constellation" = 'sagittarius' AND "Object type" = 'diffuse nebula' AND "Declination ( J2000 )" = '°02′';