What is the c (nf/km) when the r (ω/km) is 463.59?
CREATE TABLE "characteristics_of_telephone_cable_as_a_" (
  "frequency_hz" text,
  "r_km" text,
  "l_m_h_km" text,
  "g_s_km" text,
  "c_n_f_km" text
);
SELECT "c_n_f_km" FROM "characteristics_of_telephone_cable_as_a_" WHERE "r_km"='463.59';