CREATE TABLE table_28248 ("Stage" FLOAT, "Winner" TEXT, "General Classification" TEXT, "Points Classification" TEXT, "Young Rider Classification" TEXT, "Teams Classification" TEXT)

How many stages did Team Sky lead the teams classification?
SELECT MAX("Stage") FROM table_28248 WHERE "Teams Classification" = 'Team Sky'
SELECT MAX("Stage") FROM "table_28248" WHERE "Teams Classification" = 'Team Sky'