What is the Parts-per example of 2×10 −6?
CREATE TABLE "iupap_s_uno_proposal" (
  "coefficient" text,
  "parts_per_example" text,
  "uno_equiv" text,
  "symbol_form" text,
  "value_of_quantity" text
);
SELECT "parts_per_example" FROM "iupap_s_uno_proposal" WHERE "value_of_quantity"='2×10 −6';