When programming a scanner, you want to use the number in the first bold FREQUENCY column. If there are two different frequencies listed, the agency mobiles listen to the frequency listed in the first column but transmit on the second, different INPUT frequency (duplex operation) into the agency's repeater. The repeater then repeats everything it hears coming in on the INPUT frequency back out on the first main frequency. This allows the voices from every mobile radio in their fleet to be retransmitted from a base antenna over a wide area.
Not all systems use repeaters, and the second INPUT column will be blank. If a radio transmits in simplex (listening and talking on the same frequency) hearing them is dependent on how well your radio can pick up their possibly distant or weak signal. Even if an agency does have a repeater some base stations and mobiles may both listen and talk simplex on the primary first column frequency.
Each row is typically a different channel. You may see the same first column frequency in multiple rows. This means that there is more than one transmitter or agency on the same frequency, or that the same agency uses the frequency in both duplex and simplex mode. Always remember that a frequency is the radio wavelength of a signal, while channel refers to a complete set of frequencies and squelch tones that define it under a more easily remembered common name.
You can program the INPUT frequencies, but agencies spend thousands of dollars on repeaters and towers to pick up weak mobiles on the INPUT and re-transmit the voice on the frequency found in the primary first FREQUENCY column with lots of power from a tall antenna that everyone can hear. You normally don't hear anything different on the INPUT frequency, so let the agency do all the heavy lifting for you. Can't hurt to check but don't be surprised if you hear very little, or only distant scratchy voices.
The INPUT column is normally of greater interest to those of us who work in the radio industry- RR provides this information along with user supplied verification as an invaluable public service!