CREATE TABLE table_58494 ("Name" TEXT, "Years" TEXT, "Area" TEXT, "Authority" TEXT, "Decile" TEXT, "Roll" TEXT)

What is the roll number of Poroti school, which has a 6 decile?
SELECT "Roll" FROM table_58494 WHERE "Decile" = '6' AND "Name" = 'poroti school'
SELECT "Roll" FROM "table_58494" WHERE "Decile" = '6' AND "Name" = 'poroti school'