The only difference is the order of the resistors and LEDs.
Look at just one of the resistor/LED pairs. The supply voltage, 6.0 V, causes a current to flow through them. The current is determined by the resistance of the resistor and the voltage drop of the LED.
In each case 26.302 mA flows through the resistor and LED. This current will cause a voltage drop across the resistor according to Ohm's Law $$ V = {I}\cdot{R}$$ So $$ V = {0.0263~A}\cdot{200~\Omega} = 5.26~V $$ and the voltage across the LED is $$ 6.0~V - 5.26~V = 0.74~V $$
In one schematic the LEDs are on top, so you are measuring the voltage across the resistor, 5.25 V, in the other the the resistor is on top so you are measuring the voltage across the LED, 0.74 V. In a series circuit it doesn't really matter which order the components are in, it will work either way.
The voltage drop across an LED, called the forward voltage is determined by the semiconductor materials it is made from. Different color LEDs have different forward voltages. Infrared ones have the lowest, down to maybe 1.2 V, ultraviolets can be over 4.5 V. The voltage also increases with increasing current.
The LEDs in your circuits are only showing 0.74 V @ 26 mA, which is probably because they are not modeled properly in whatever simulator was used.